Getting Wired for Wireless: Resiliency

We’re continuing with our Wired for Wireless series where we’ve already talked about performance, and power. This blog will discuss the importance of resiliency.

Resiliency in networking has always been essential. This is especially true as the number of devices per user increases, along with an ever-growing dependence on Wi-Fi access points (APs), and in turn, the underlying switch infrastructure. Although the move to cloud-based applications has decreased the need for in-house data, it makes reliable access to the network even more critical for operations.

One of my favorite examples to illustrate this point is a classroom with students engaged in blended or digital learning. Imagine if the classroom lesson is disrupted because the teacher or students suddenly can’t access the cloud for online tests or lessons. What does the teacher do then? Consider another scenario: a large company or SMB. Think of the negative impact on operations and employee productivity if critical applications such as Salesforce or VoIP phones were suddenly inaccessible.

Fortunately, network resiliency is available in many forms, such as redundant components in the switch. Most often, that’s the power supply or the fans. Having two or more of each reduces the chance of a failure – preferably hot-swapped so that they’re easily field replaceable. Similarly, having redundant links ensure that connectivity isn’t lost if a single link goes down. However, not all dual links are the same. In some cases, they are active-passive, where the alternate link is idle unless there’s a failover. On the other hand, active-active links provide load balancing over both links until there’s a failure. Extending this approach by creating dual paths from each switch to the aggregation in-core eliminates a single point of failure for any switch, as well as over any link.

Additional resiliency can be made available within stacks of switches. For example, hitless failover ensures that a failure of a single switch does not take down the stack – and enables the painless re-insertion of a replacement switch in the stack. Moreover, advanced features such as Ruckus’ in-service software upgrade (ISSU) provides an incremental method to upgrade traditional stacks. More specifically, a successful ISSU does not affect uplink or downlink connectivity in a topology with multi-unit LAGs. Only the node that is undergoing the upgrade requires a hardware reset (which includes the reset of the packet processor). As a result, traffic transiting only that node is disrupted.

Ruckus switches offer all the above-mentioned forms of resiliency. They are available across our entire ICX switch lineup: dual power supplies and fans, redundant links, load balancing, hitless failover, as well as our very own in-service software upgrade feature.